In the embodiment of the invention of Japanese Unexamined Patent Publication No. 9-85833 (Patent Document 1), there is disclosed a technology for executing a vibration welding process by bringing two work pieces made of a thermoplastic material into contact with each other in a face to face manner.
In the embodiment of the invention of Japanese Unexamined Patent Publication No. 9-151723 (Patent Document 2), there is disclosed a technology for executing vibration welding of two work pieces brought into contact with each other by a fixed side tool and a vibration side tool.